1. Field of the Invention
Example embodiments of the present invention relate to a semiconductor device and methods of fabricating the same. Other example embodiments of the present invention relate to a fin-field effect transistor (Fin-FET) having a fin-type channel region and methods of fabricating the same.
2. Description of the Related Art
As semiconductor devices become more highly integrated, design rules for components of semiconductor devices have become more stringent. For example, a gate length, which is a standard of the design rule, may decrease for semiconductor devices requiring more transistors. As the gate length decreases, a channel length may also decrease. A decrease in the channel length of a transistor may increase a short channel effect.
The short channel effect refers to a phenomenon wherein an effective channel length of a transistor decreases as a result of an effect of a drain potential and decreases in a threshold voltage. As the effective channel length of the transistor decreases, controlling the transistor becomes more difficult and an off current of the transistor increases, degrading the reliability of the transistor. For example, refresh characteristics of a memory device may also degrade.
Research of a fin-field effect transistor (Fin-FET), which is a transistor having a fin-channel structure using several surfaces of a thin fin as a channel, has been acknowledged by the conventional art. A short channel effect, which causes problems in a conventional planar transistor, may be prevented (or reduced) and simultaneously an operation current may increase.
For example, the conventional art discloses a Fin-FET and a fin memory cell. In the Fin-FET, top and side surfaces of a fin may be used as a channel region. The conventional art also acknowledges a Fin-FET wherein portions of side, upper and lower surfaces of a semiconductor fin may be used as a channel region.
Fabricating the Fin-FETs using an SOI substrate, may increase the manufacturing cost. Because a lower surface of a fin may not be entirely used as a channel region, the operating current may be limited.